Dynamo-electric machine.



D. HALL.

DYNAMO ELEGTRIG MACHINE. APPLICATION FILED JAN. 31, 1906.

91 6,928. Patented Mar. 30, 1909.

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Armem UNITED STATES DAVID HALL, OF NORWOOD, OHIO, ASSIGNOR TO THEBULLOCK ELECTRIC MANUFACTURING PATENT OFFICE.

COMPANY, A CORPORATION OF OHIO.

DYNAMO-ELE CTRIC MACHINE Specification of Letters Patent.

Application filed. January 31, 1906.

Patented March 30, 1909.

Serial No. 298,752.

To all whom it may concern:

Be it known that I, DAVID HALL, citizen of the United States, residingat Norwood, in the county of Hamilton and State of Ohio, have inventedcertain new and useful Improvements in Dynamo-Electric Machines, ofwhich the following is a full, clear, and exact specification.

My invention relates to dynamo-electric machines of the type havingauxiliary or commutating field poles intermediate the main field polesfor reducing sparking at the brushes.

It is sometimes a difficult matter to so design the machines that thecommutating fields are of just a proper intensity to reduce sparking atthe brushes to a minimum. This is es ecially true of large machinesdesigned for eavy currents. As the auxiliary field windings are usuallyin series with the armature, and carry the entire armature current, itis seen that a very slight error in the number of turns has considerableeffect on the ampere-turns of the poles. Furthermore, on account of theinequalities in the material employed and for other causes thereluctance of the magnetic circuit through one pair of auxiliary polesmay be different from the reluctances of the circuits through the otherpairs of poles, which condition results in unsatisfactory commutation.

The object of my invention is to provide means whereby the intensity ofthe commutating fields can be adjusted so that the sparking at eachbrush can be eliminated or reduced to a minimum. With this end in View Iprovide auxiliary field poles the inner end-portions of which can beadjusted, whereby the air gap and reluctances of the magnetic circuitscan be changed.

More specifically considered my invention consists in a dynamo-electricmachine having main field poles, and auxiliary field poles intermediatethe main field poles, each auxiliary field pole comprising a normallyfixed main portlon and an adjustable inner end portion, the two partsbeing dove-tailed together and their adjacent surfaces being inclined tothe axis of the machine, whereby the effective lengths of the auxiliaryfield poles can be adjusted.

My invention still further consists in the details of construction andcombinations of parts described in the s ecification and set forth inthe appended c aims.

For a better understanding of my invention, reference is had to theaccompanying drawing in which Figure 1 is a partial sectional elevationof a dynamo-electric machine having my invention applied thereto; Fig. 2is a partial end elevation of the commutator end of the machine, theshaft being shown in section and Fig. 3 is an elevation of a portion ofthe field frame and one of the auxiliary field poles, the view beingtaken from the opposite end of the machine.

Referring now to the figures of the drawing, I have shown at 10 theshaft of the machine on which are mounted the commutator 11 and thearmature 12. Surrounding the armature is the field frame 13 havinginwardly extending main field poles 14 which carry main field coils 15.Intermediate the main field poles are the auxiliary field poles 16,provided with auxiliary field coils 17. The object of these coils andpoles which are supported opposite the brushes is, as is well known, toprovide commutating fields for the armature coils short-circuited by thebrushes, in order to reduce s arking at the brushes. The auxiliary fielcoils in this case consist of edgewise wound strap copper, the fieldcoils being held in place by supports 18 secured to the field poles bybolts 19.

Each auxiliary field pole, as is shown most clearly in Fig. 1, comprisesa normally fixed I main portion 20 and a movable portion 21 at the inneror armature end of thepole. The two portions of each pole are heldtogether in this case by a dove-tailed joint, and adjacent surfaces ofthe parts are inclined to the axis of the machine so that when the endportion is moved in the direction of the axis of the machine it willalso be moved in a radial direction to vary the effective length of thepole. As is shown in Figs. 1 and 3, each adjustable end portion 21 isprovided at one side with anextension or neck portion 22. This extensionis provided with a hole or opening and the corresponding fixed portionof the pole is provided with a tapped opening, the two openings being inline with each other and arranged parallel to the adjacent surfaces ofthe two parts. A screw or bolt 23 has a threaded portion engaging thetapped hole in the fixed portion of the pole and an unthreaded portionengaging the extension 22. Collars 24 and 25. fixed to the bolt at eachside of the neck or extension 22 prevent longitudinal movement of thebolt relative to said neck portion. The outer end of the bolt ispreferably provided with a squared end portion by means of which thebolt can be turned. It is seen that by adjusting the bolts 23 themovable end portion 21 of each auxiliary field pole can be adjusted,being moved both longitudinally and axially of the armature. Thus theeffective length and hence the effective air gap of each auxiliaryfield-pole can be separately adjusted and therefore the reluctance andthe intensity of each auxiliary magnetic field circuit can be increasedor descreased by adjusting the position of the inner ends of the poles.

I do not wish to be confined to the exact details shown, as manymodifications can be made without departing from the spirit and scope ofmy invention.

What I claim as new and desire to secure by Letters Patent. is

1. In a dynamo-electric machine, main and auxiliary field poles havingfield coils, the inner portion of each of said auxiliary poles beingadjustable in its entirety and independently of the rest of the polewhereby the effective length of said pole can be changed.

2. In a dynamo-electric machine, main field poles, field coils thereon,auxiliary field oles intermediate the main field poles, auxi 'ary fieldcoils or commutating coils on said last named field poles, and means foradjusting the entire inner ends of the auxiliary field polesindependently of the bodies of said pojes to change the effectivelengths of said p0 es.

3. In a dynamo-electric machine, an armature, field poles having fieldcoils, and auxiliary field poles having commutating coils, eachauxiliary pole comprising two parts, the entire inner parts of theauxiliary field poles being adjustable toward and away from the armatureto change the reluctance of the auxiliary field magnetic circuits.

4. In a dynamo-electric machine, an armature, main field poles havingfield coils, and auxiliary field poles intermediate the main field polesand having commutating coils, each auxiliary pole comprising tworelatively movable parts, the entire inner ends of the auxiliary polesbeing adjustable axially to vary the reluctance of the commutating fieldmagnetic circuits.

5. In a dynamo-electric machine, an armature, main field poles havingfield coils, auxiliary field poles intermediate the main field poles,commutating field coils thereon, and means whereby the inner ends ofsaid auxiliary field poles can be adjusted independently of the mainportions thereof toward and away from the armature, and longitudinallythereof.

6. In a dynamo-electric machine, an armature, main field poles havingfield coils, and auxiliary field poles having commutating coils, eachauxiliary pole comprising a fixed part and a movable part, the adjacentsurfaces of which engage and are inclined to the axis of the armature.

7. In a dynamo-electric machine, an arma ture, main field poles havingfield coils, auxiliary field poles having commutating coils, and meanswhereby the inner or armature end of each auxiliary field pole can beadj usted independently of the remainder thereof in a radial and anaxial direction to vary the commutating field magnetic circuits.

8. In a dynamo-electric machine, an armature, main field poles havingmain field coils, and auxiliary field poles provided with coininutatingfield coils, each auxiliary field pole comprising two relatively movableparts obliquely dove tailed together.

9. In a dynamo-electric machine, an armature, main field poles havingmain field coils, and auxiliary field poles having auxiliary orcommutating field coils, each auxiliary pole comprising two relativelymovable parts dove-tailed together, and means for adjusting and holdingin fixed positions the inner ends of said pole pieces.

10. In a dynamo-electric machine, an armature, main field poles havingfield coils, and auxiliary field poles having commutating field coils,each auxiliary pole comprising a normally fixed main portion and anadjustable inner end portion, the two parts of each pole beingdove-tailed together, and

the adjacent surfaces of the two parts being inclined to the axis of themachine.

11. In a dynamo-electric machine, an armature, main field poles havingfield coils, auxiliary field poles having commutating field coils, eachauxiliary field pole consisting of a normally fixed main portion and anadjustable inner end-portion, the two parts being dovetailed togetherand the dovetailed portions being inclined to the axis of the armature,and means for adjusting and holding in fixed positions the movableportion of each auxiliary pole.

1.2. In a dynamoelectric machine, an armature, main field poles havingfield coils, auxiliary field poles having auxiliary or commutating fieldcoils, each auxiliary field pole comprising a main portion and an innerend portion adjustable only in its entirety, and means engaging the mainportion and the inner end portion of each pole for adjusting and holdingthe movable portions in fixed )ositions. I

13. .n a dynamoelectric machine, an armature, and a field frame havingmain field poles and. auxiliary field poles, each auxiliary field polecomprising a relatively fixed portion and a movable end portion, thelatter having at one side an extension or neck and a screw or boltengaging the extension and the fixed portion for adjusting the positionof the movable portion.

14. In a dynamo-electric machine, a field pole comprising a fixed mainportion, and a movable inner end portion arranged to be moved in adirection oblique both to the axis of said pole and to the axis ofrotation of the machine.

15. In a dynamo-electric machine, an

armature, and a field pole comprising a fixed main portion and an endportion, the latter portion being adjustable in its entirety to 15 varythe air gap between the field pole and the armature.

In testimony whereof I aflix my signature in the presence of twoWitnesses.

DAVID HALL.

l/Vitnesses ARTHUR F. KWIs, FRED J. KINSEY.

